Image Artifact: Self-Similar Triangles

One common problem encountered in AFM imaging is image artifacts due to a damaged tip. The tip is at the end of a triangular pyramid, and if that pyramid is sheared it will be a small triangular area that is interacting with the surface, not a sharp tip. The result will be self-similar triangular artifacts in the image.

This is a tapping AFM image of the tip qualification standard. Even if one did not anticipate seeing sharp edges to the grains at the film surface, in AFM imaging it is always suspicious when all of the features are self-similar in shape. Many features look triangular. It is also a cause for concern in AFM imaging when all of the features are unnaturally oriented: every triangle is oriented in the same direction with one point towards the +X-direction. Every triangle is also a perfect equilateral triangle. It would be too coincidental to have such perfect alignment of surface structures.